1. Field of the Invention
The present invention relates to an aberration correcting device and an optical recording medium reproducing apparatus.
2. Description of the Related Art
Conventionally, in a technical field of an optical pickup for reading the recorded information of an optical disk, aberration correction employing a liquid crystal panel is conducted to read a plurality of kinds of optical disks with one objective lens. For example, in JP-A-9-128785, to reproduce both DVD and CD with one objective lens, an optical pickup that corrects an aberration occurring in the objective lens by controlling the applied voltage of the liquid crystal panel in accordance with a disk thickness has been disclosed.
JP-A-9-128785 is referred to as a related art.
With the conventional technique as described above, although the aberration occurring in the objective lens is corrected, the numerical aperture (NA) of each disk is not directly dealt with. It results in a problem that aperture restriction has to be made separately from the aberration correction by shielding the light through a liquid crystal shutter to deal with the numerical aperture.
Therefore, one of the problems to be solved by the invention is that “when an objective lens having a different aperture diameter is employed for a certain disk, it is required to make the aperture restriction separately from the aberration correction”.